1. Field of the Invention
This invention relates to electrical power distribution systems and, more particularly, to electrical power distribution systems employing a disconnect and a surge protector. The invention also relates to electrical power distribution systems employing a main disconnect, a surge protector, and a plurality of meters.
2. Background Information
Main disconnect units include load centers, motor control centers, busways, panelboards, switchboards, switchgear, circuit breakers, fuses, and switches for interrupting electrical power between a power source and one or more loads.
Meter centers are often used in combination with main disconnect units in order to provide metering of electrical power delivered to multiple tenants from a common feeder system. Typically, the meter center includes an upright cabinet forming an enclosure divided into side-by-side meter and disconnect switch compartments. Feeder buses, typically three phase buses and a neutral bus connected to the electric utility lines, extend horizontally through the rear of the cabinet. The meter compartment has pairs of vertical supply buses. Each pair of the vertical supply buses is connected to a selected pair of the feeder phase buses. In turn, a pair of tenant buses for each metered circuit extends horizontally from the disconnect switch compartment into the meter compartment. See, for example, U.S. Pat. No. 6,012,937.
If surge protection is desired, then customers (e.g., owners of buildings having multiple tenants, such as offices or apartments) would have to purchase separate surge protection devices and wire those surge protection devices into the electrical power distribution system themselves.
Alternatively, the individual tenants may employ surge protection strips at selected power outlets.
There is a need, therefore, for an improved electrical power distribution system which is capable of withstanding surges.
There is also a need for such an improved electrical power distribution system, which reduces the labor required to install and remove a surge protection device in the electrical power distribution system.
Accordingly, there is room for improvement.
These needs and others are satisfied by the invention which is directed to an electrical power distribution system comprising a disconnect unit including an electrical power bus having a plurality of power lines, and means for interrupting current flowing in the power lines; and a surge protector unit including an electrical power bus having a plurality of power lines, and means for protecting at least one load from surges or transients on the power lines. The electrical power bus of the surge protector unit electrically engages the electrical power bus of the disconnect unit to form a series electrical connection of the electrical power buses for the at least one load.
Preferably, the electrical power bus of the surge protector unit has a first end and an opposite second end, the electrical power bus of the disconnect unit has a first end and an opposite second end, and one of the first and second ends of the electrical power bus of the surge protector unit is secured to one of the second and first ends, respectively, of the electrical power bus of the disconnect unit.
As another refinement, each of the units includes an enclosure, and each of the electrical power buses includes a first rigid bus bar and a second rigid bus bar. The first rigid bus bar is offset at a first end and projects beyond the enclosure at a second end. The second end extends into a gap between the offset of the first rigid bus bar of an adjacent one of the units and is clamped by a fastener to electrically connect the electrical power buses of side by side ones of the units.
As another aspect of the invention, an electrical power distribution system comprises a main disconnect unit including an electrical power bus having a plurality of power lines, and means for interrupting current flowing in the power lines; a surge protector unit including an electrical power bus having a plurality of power lines, and means for protecting a plurality of loads from surges or transients on the power lines; and a multiple meter unit including a meter for each of the loads and an electrical power bus having a plurality of power lines. The electrical power buses of the main disconnect unit, the surge protector unit and the multiple meter unit are electrically connected in series, and the electrical power bus of one of the units electrically engages the electrical power buses of the other two units.